Soil biology plays a major role in determining soil charcateristics since the decomposition of organic matter by various soil organisms has a large impact on soil fertility, plant growth, soil structure and carbon storage. In fact, 80% of all life on the planet occurs in soils and, quite amazingly, the weight of all the earthworms on the planet is greater than that of all the other animals and insects together !
It is only recently that comprehensive research has been carried out to develop an understanding of how this complex world impacts plant life and how it may affect wine quality since enzymes play a key role in the winemaking process and especially the formation of aromas. These enzymes occur naturally in grapes and yeats (although they can be commercially produced – another subject!) and have the effect of releasing the aromatic components from their odourless aroma precursors. To function correctly they need mineral elements (copper,magnesium, mangenese, nickel,, iron, sodium, zinc) in order to facilitate this aromatic development and if they don't have the necessary mineral supply aromatic complexity may be impaired.
In the next article the essential rôle played by various microrganisms in facilitating mineral uptake by the vine will be discussed in more detail. However it is sufficient to point out that in conventional agriculture with the use of synthetic chemicals the roots of the vine don't go down very deep and consequently the vine can have difficulty sourcing these elements. Pre-phyloxera & pre-mechanisation vine roots would descend to 3m whereas 50cm is not uncommon today. And perhaps more importantly, the use of chemicals can have a disasterous effect on the microbial activity of the soils.